I've just attempted to replace my E250's HK center dash speaker as it was rattling and distorting. I got the OEM replacement from my local dealer.

I followed the instructions to remove the cover that were usefully posted here: https://mbworld.org/forums/e-class-w...2014-w212.html

The speaker itself is just press fit and removes easily with a little bit of pressure. However, I was quite surprised to find two sets of two wires connected to the speaker, each pair via one quick connector. One quick connector is black and one is white. Unfortunately I broke the white one while trying to remove it from the old speaker. I have ordered the quick connector from my local dealer so I should be able to replace it no problem.

However, I decided to test what the wires do when connecting the new speaker. The black connector (which I did not break) powered the speaker when I hooked it up. The wires that were attached to the white connector did not seem to do anything at all when I temporarily connected them to the speaker. They didn't seem to do anything on their own or when the black connector was connected. No discernible increase or change in output.
I don't know if this is how it should work or if there is another problem. Maybe I blew the amplifier channel that corresponds to the white connector somehow?

Which brings my to the question: Does anybody know why the HK center channel speaker has two sets of connections? What is the purpose of the white connector? Are both necessary? Any information or wiring diagram would be greatly appreciated. Thanks in advance for any help.

Right now I have only the black connector attached to the center channel driver. I taped off the other wires waiting for the connector from the dealer and put everything else back together.

 

Interesting... I do not have the answer, but did you try turning Logic7 on/off and testing what happens in regard to the white connector?

 

I’m awaiting a replacement white connector from the dealer. I’ll try that experiment when it arrives next week and let you know. Thank you for the suggestion! For now the dash is put back together.

 

My guess (and this is just a guess) is that this may be a dual voice coil speaker. It may be receiving signals related to both the right and left channels. If the signals are sent in an out-of-phase condition, they may enhance the apparent channel separation of left versus right.

There used to be a high-end home stereo speaker system that did that -- the Polk Audio SDA-1. I had a pair of these monsters in the 1980's. In each cabinet (right and left) there were numerous speakers, but there was one speaker actually wired to the opposite side channel, with reversed polarity/phase. This so enhanced the channel separation that one could close their eyes while listening to the system and point to where the sound of some instrument came from. Opening their eyes, the listener found that the spot they were pointing to was nowhere near either of the speaker cabinets. Polk called the phenomenon "Psycho-Acoustic Imaging." Really slick. Too bad those monsters were so big and plain -- had to replace them to keep peace in the castle.

 

I had my first experience using MBRACE the other day and it seems to only come out of the center speaker.. could perhaps also be related to that? It certainly sounded crappy.

 

SteveE400, you are correct that it is a dual voice coil speaker. At least it appears to be, as there are two sets of leads going to the center of the driver - one from each connection point. If I get really bored I might dissect the old unit to find out.

Your theory with the Polk speakers is fascinating. Indeed, Polk has recently revived the technology in a new high-end speaker: https://www.stereophile.com/content/...event-montreal However, I believe that such a strategy with in and out of phase drivers must indeed employ separate drivers. If a dual voice coil driver is fed out of phase signals they will simply cancel and eliminate the output, similar to if the out-of-phase signals are summed and fed to a normal driver. I thought perhaps the two voice coils might be for higher and lower frequencies, even though I've never seen such a scheme in a driver, but nothing in my experimentation leads me to that conclusion.

The new connector arrived yesterday and I installed it and did quite a bit of experimentation. I hooked up the black and white connectors in turns and confirmed that the stereo makes no sound through the white connector with or without Logic7 Surround enabled. Nor does the white connector function for navigation voice cues, voice command cues, parking sensor beeps, or phone calls.

LILBENZ230, I did actually test pressing one of the MBRACE buttons and I couldn't hear anything. I don't know if that's because I've never subscribed to it or because of a technical issue. Now that you mention it I think your theory is quite likely, but I can't for the life of me remember if I tested MBRACE with the white connector hooked up or only the black. Does anybody else know if MBRACE runs on a separate circuit? Could this be to preserve emergency function if the amplifier is destroyed during a rear-end accident? If I should be able to hear something even though I don't subscribe, I can do another test to see what happens.

The Mercedes dealership said that the wiring diagram and answer is likely in STAR TekInfo, although they were unsure of what the white connector is for. Anybody with access want to help out? $60 for 24 hours of access is a little steep just to satisfy my curiosity.

 

I stumbled across the answer reading an unrelated thread. Looks like you were right, @LILBENZ230 . Seems to that the second voice coil and lead are exclusively for MBRACE. As I don't intend to subscribe, I'm just going to leave it as-is for now.

 

Interesting. The door panel speaker covers look like two speakers are behind them, one large and one small. But when he pulls the panel it looks like just one large speaker.

 

There is a midrange speaker. It looks very much like the center channel. But it is mounted on the door trim panel, rather than the metal panel. You can see it towards the bottom of this post: https://mbworld.org/forums/w212-amg/...ml#post7209406

 

Ah ha. That clears it up. Thanks!

 

I broke both the black and white connectors. Do you know the name or part number for these?

 

Connectors to what exactly, also provide VIN.